The invention relates to an ignition trigger device for an underwater projectile.
In a known ignition trigger according to DE-OS No. 31 33 364 a pressure transducer is loaded by a spring so that with an adequate velocity of the projectile underwater, a switch is being kept open by dynamic pressure acting against the spring force. Only when the surface of the water is breached, is the switch closed, thereby triggering the ignition. The point in time of the switch closing in this ignition triggering device depends on the spring characteristic, which limits possible uses of the device to the extent that it is not possible to use the impact on the target as the switching criterion, if it is designed to ignite upon leaving the water. The response sensitivity of the ignition trigger device according to DE-OS No. 31 33 364 depends on the spring built into it and therefore may only be set relatively coarsely and in practice cannot be subsequently adjusted. This ignition trigger device also has the further disadvantage that sealing problems may occur, because on the one hand the pressure transducer must be mobile relative to the head, and on the other, it must be well sealed against said head.
In an ignition trigger device according to DE-OS No. 34 14 841 these deficiencies are eliminated. In that device, a piezo-ceramic disk equipped with electric contacts is disposed in the projectile head. The disk is rigidly supported on one of its sides, and its other side rests against a pressure transducer body supported in the opening of the head.
In this manner, the dynamic pressure is acting on the piezo-ceramic disk. Any variation of the dynamic pressure results in a corresponding stress or potential variation of the piezo-ceramic disk, which may be processed in an electronic evaluating circuit in a manner such that the variation in the potential may be used as a switching criterion. It is further possible with the ignition trigger device of DE-OS No. 34 14 841 to employ the exit from or entry into the water, together with the impact of the projectile, as the switching criterion for ignition. The disadvantage of this known ignition trigger device is that a certain dynamic pressure must act on the piezo-ceramic disk in order for it to carry out the necessary functions.